Push buttons conforming to the above description are well known in the state of the art. They are, for example, fitted to chronographs or wristwatches for correcting, for example, the date. They are called “push buttons” when they protrude from the middle part and correct a function when pressed with a finger. When the pressure ceases, the push buttons return to their initial position. They are usually called “correctors” when they are embedded in the middle part of the watch. In principle, each push button is linked to the correction of a single function; thus where there is a plurality of functions to be corrected, a plurality of push buttons must be fitted to the middle part of the timepiece, which then weakens the sealing of said timepiece.
The idea of the present invention is to give a conventional push button an additional function, to avoid further piercing the timepiece. The additional function may consist of a valve fitted to a diver's watch.
For the reasons set out above, CH Patent Application No 699 558 A1 has already proposed a screw-in winding crown associated either with a push button, or with a valve in a single control device. There is no description or suggestion of a combined push button-valve.
As is well described in the aforecited document, diver's watches often include both a winding crown and a valve to prevent the watch exploding when the diver returns to the surface. Indeed, as explained in said document, professional divers descend to great depths to carry out work and are then returned to the surface using a pressurised chamber which controls the decompression stops required for the diver's health. During these decompression stops, gases—essentially helium—penetrate the divers' watch case through the sealing gaskets which are essentially suited to preventing water or dust from entering inside the watch. When the pressure in the chamber drops during decompression stops, if there is no pressure balance device in the watch, excess pressure may build up inside the watch relative to the surrounding pressure, which may cause the watch to explode. In diver's watches, a valve is arranged separately from the other controls for the pressure balance. However, this valve suffers from the same drawbacks as those affecting push buttons or crowns with respect to sealing problems.